Since I’ve mentioned it a couple of times in my posts, I thought I’d provide an example of the knees I had to hike and ride with for years. In the photo below, I’m the hunched guy on the left. Note in particular the right leg. The knock was severe enough that by 2011 I not only had to give up hiking, but I wasn’t able to ride my road bike any longer as even with extenders on the spindles I couldn’t get my right foot on the pedal. I was able to ride my hybrid, since that bike had longer spindles to begin with.

Here’s before and after. The photo on the left is from a May 2011 bike ride. Notice my right foot is angled out 25 degrees in addition to the knock. Also, the left doesn’t have a full extension, which meant I basically walked with my knees bent. Despite my joints I hiked up a small mountain in 2010, rode a two week tour in 2009, and did a century ride in 2007. But by 2011 I’d given up hiking, and cycling was over by year end. 
The photo on the right is July 2012, five months after surgery. Same bike, same jersey, but my legs are straight and I’m two inches taller from the straightening of the legs and the additional height the artificial joint gives me. (The artificial joint is larger than the natural knee.)

Since the surgery I’ve beaten my best previous hikes in distance. This past winter I walked the bike trail in Valley Forge for seven miles, which beats my January 2007 six mile hike in Philadelphia. Also, after the 2013 hike I felt sore but otherwise OK. I felt like I was going to die after the Philadelphia walk in 2007. While riding hasn’t seen the same success, I’m gradually increasing my stamina and I expect to be back to my previous level of activity by the end of the year. 
Artificial knees aren’t a cure all, especially for the outdoorsman. While I have little or no knee pain any longer, I can still have swelling after strenuous or long exercise, and in the rain as well. Still, its an improvement over my diseased joints. I pushed myself to my limits before. I’m finding out what those limits are now on my new joints.